Bicycle exerciser



FIG. 1 is a right side perspective view of a bicycle exerciser showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a front elevational view thereof. 

The ornamental design for a bicycle exerciser, as shown. 